One person was killed Monday afternoon at an apartment building in the 400 block of Alexander Street.

Police said the tenant told investigators he shot an intruder in self-defense after the person tried to break into his first-floor apartment.

"The resident of the first-floor apartment apparently ran to another resident's apartment and asked that she alert police that he had to shoot an intruder breaking into his home," said McKees Rocks Police Chief Robert Cifrulak.

The victim, who was shot in the chest and head, has not yet been identified.